The field of this invention is the thermoregulatory status of mammals.
Human body temperature is normally tightly controlled by an autonomic regulatory system referred to herein as the thermoregulatory system. The most important effector of this regulatory system is blood flow to specialized skin areas where heat from the deep body core can be dissipated to the environment. Normally, when body and/or environmental temperatures are high, the dilation of certain blood vessels favors high blood flow to these surfaces, and as environmental and/or body temperatures fall, vasoconstriction reduces blood flow to these surfaces and minimizes heat loss to the environment.
There are situations, however, in which it would be desirable to be able to manipulate the transfer of heat across the skin surfaces to provide for regions of different temperature in the mammalian body, i.e., to provide for a temperature gradient in the body made up of at least two different temperature compartments. Such temperature compartmentalization would be useful in a number of applications, including therapeutic treatment regimens, as described in greater detail below. However, temperature compartmentalization of the mammalian body is difficult to produce, as attempts to create such compartmentalization are impeded by the compensatory actions of the thermoregulatory system.
As such, there is great interest in the development of methods in which the thermoregulatory system is manipulated so that energy can be transferred into or out of the thoracic/abdominal core body without triggering concomitant opposing reaction by the thermoregulatory system.
Relevant Literature
U.S. Pat. No. 5,683,438. See also WO 98/40039. Also of interest are: Soreide et al., xe2x80x9cA non-invasive means to effectively restore normothermia in cold stressed individuals: a preliminary report,xe2x80x9d J Emerg. Med. (1999 July-August)17(4):725-30 and Grahn et al., xe2x80x9cRecovery from mild hypothermia can be accelerated by mechanically distending blood vessels in the hand,xe2x80x9d J. Appl Physiol. (1998) 85(5):1643-8.
Methods and devices for manipulating the thermoregulatory status of a mammal are provided. In the subject methods, thermal energy is transferred between the environment and both of the thoracic/abdominal and head regions or compartments of the core body of the mammal. In general, thermal energy transfer between the thoracic/abdominal region of the core body and the environment occurs under negative pressure conditions. The subject methods and devices can be used to increase the thoracic/abdominal temperature of a mammal, in which case thermal energy is introduced into this region or compartment of the core body of the mammal and removed from the head of the mammal. The subject methods and devices can also be used to reduce the thoracic/abdominal temperature of a mammal, in which case thermal energy is removed from this region of the core body of the mammal and introduced into the head of the mammal. The subject devices include at least the following components: (a) a means for causing a transfer of thermal energy with the thoracic/abdominal region of the core body of a mammal under negative pressure conditions; and (b) a means for causing a transfer of thermal energy with the head region of the core body of the mammal. The subject methods and devices find use in a variety of applications, and are particularly suited for use in producing a thermal gradient in a mammal, e.g., one in which the thoracic/abdominal core body is warmer or colder than the head.